Fluid cooled optical fiber

ABSTRACT

Fluid cooled optical fibers are disclosed. An exemplary fiber comprises a fiber body including a distal end, an inner cap surrounding said distal end, an outer cap surrounding said inner cap, and a tube attached to said outer cap. The tube and outer cap may define a first flow channel, the outer and inner caps may define a second flow channel, and the outer cap may including one or openings for placing the first flow channel in communication with the second flow channel. Associated systems also are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 15/847,650, filed Dec. 19, 2017, which claims the benefit ofpriority to U.S. Provisional Application No. 62/436,530, filed Dec. 20,2016, the disclosure of each of which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

Aspects of the present disclosure generally relate to optical fibers.Particular aspects relate to a fluid cooled optical fiber.

BACKGROUND

Liquid cooled optical fibers may be used in laser systems to providefast and efficient discharge of laser energy. Some liquid cooled fibersmay include a single, continuous flow channel for directing a coolingliquid (e.g., water) about the fiber and/or a distal cap of the fiber.The interface between the optical fiber, tube, and distal cap is a knownproblem area. For example, gradual loosening of the distal cap is aknown problem. Cap loosening may occur when the distal cap becomesmoveable relative to the laser fiber because of heat generated from thelaser energy. A loose cape failure occurs when some portion of the capmoves into the laser energy, generating even more heat. To avoid loosecap failure, many liquid cooled fibers are replaced prematurely, addingexpense. Cap failure may also occur during a procedure, requiring thesurgeon expend additional operation time, adding even more expense. Thepresent disclosure addresses these problems and other deficiencies inthe prior art.

SUMMARY

Aspects of the present disclosure relate to a fluid cooled opticalfiber. Numerous aspects of the present disclosure are now described.

One aspect of this disclosure is an optical fiber. The fiber maycomprise: an fiber body including a distal end with a reflective surfaceangled to direct laser energy out of the body along a laser axis; aninner cap surrounding the distal end of the fiber body, the inner capincluding a proximal end attached to the fiber body, and at least onetransmission portion aligned with the laser axis; an outer capsurrounding the inner cap, the outer cap including a proximal endattached to at least one of the inner cap and the fiber body, and anexit port aligned with the laser axis; and a tube surrounding at leastportion of the fiber body, the tube including a distal end attached tothe outer cap. According to this aspect, the tube and the outer cap maydefine a first flow channel, the outer cap and the inner cap may definea second flow channel, the outer cap may include one or more openingsconfigured to place the first flow channel in communication with thesecond flow channel, and/or the one or more openings may be distal ofthe proximal end of the inner cap.

In some aspects, the proximal end of the inner cap may be attached tothe fiber body by a first epoxy. The proximal end of the inner cap mayinclude a surface feature configured to promote adhesion with the firstepoxy. An interior surface of the inner cap may be spaced part from anexterior surface of the fiber body by the first epoxy to define a sealedinterior cavity within the inner cap. The sealed interior cavity mayinclude an insulative element. The optical fiber may further compriseone or more attachment points between the interior surface of the innercap and an exterior surface of the distal end of the fiber body. Theproximal end of the outer cap may be attached to the inner cap and by asecond epoxy. The first epoxy may have a property different than that ofthe second epoxy. The second epoxy may encapsulate the proximal end ofthe inner cap and an exterior surface of the first epoxy. Similar toabove, the proximal end of the inner cap may include a surface featureconfigured to promote adhesion with the second epoxy.

The one or more openings of the outer cap may be proximal of the exitport. In some aspects, the one or more openings may be positionedoppositely about the fiber body. A distal portion of the first flowchannel may converge toward the one or more openings, and/or the secondflow channel may include an expanded interior portion adjacent the exitport. In any of these aspects, the inner cap may be made of a glass andthe outer cap is may be made of a metal.

Another aspect is an optical fiber tip comprising: an inner capincluding an interior cavity sized to receive an optical fiber, aproximal end engageable with the optical fiber, and at least onetransmission portion; and an outer cap including an interior cavitysized to receive the inner cap, a proximal end engageable with at leastone of the inner cap and the optical fiber, an exit port, and one moreopenings. According to this aspect, when the inner and outer cap arecoupled together, the at least one transmission portion may be alignedwith the exit port, the outer cap and the inner cap may form a flowchannel, and the one or more openings may be distal of the proximal endof the inner cap.

According to this aspect, the one or more openings may extend along anopening axis transverse with the fiber body. The second flow channel mayinclude an expanded interior portion adjacent the exit port. Theproximal end of the inner cap may be coupled to the proximal end of theouter cap by an epoxy. In other aspects, the inner cap may have athermal resistance greater than a thermal resistance of the outer cap.

Yet another aspect of this disclosure is a laser system including anoptical fiber, a laser source, and a fluid source. According to thisaspect, the optical fiber may comprise: a fiber body extending between aproximal end engageable with a laser source and a distal end configuredto direct laser energy out of the fiber body; an inner cap surroundingthe distal end of the fiber body, the inner cap including a proximal endattached to the fiber body and at least one transmission portion; anouter cap surrounding the inner cap, the outer cap including a proximalend attached to the inner cap, and an exit port; a tube surrounding atleast a portion of the fiber body, the tube including a proximal endengageable with a fluid source and a distal end attached to the outercap; a first flow channel between the tube and the fiber body; a secondflow channel between the outer cap and the inner cap; and one or moreopenings extending through the outer cap to place the first flow channelin communication with the second flow channel, each of the one or moreopenings being distal of the proximal end of the inner cap.

It may be understood that both the foregoing summary and the followingdetailed descriptions are exemplary and explanatory only, neither beingrestrictive of the inventions claimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated in and constitute a part ofthis specification. These drawings illustrate aspects of the presentdisclosure that, together with the written descriptions herein, serve toexplain this disclosure as follows:

FIG. 1 depicts an optical fiber coupled to a fluid source and a lasersource according to aspects of this disclosure; and

FIG. 2 depicts an optical fiber according to aspects of this disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure are now described with reference to afluid cooled optical fiber. Some aspects are described with reference tomedical procedures where laser energy is used to treat a kidney stone.References to a particular type of procedure, laser energy, stoneobject, and/or bodily organ are provided for convenience and notintended to limit the present disclosure unless claimed. Accordingly,the concepts described herein may be utilized for any analogousfiber—medical or otherwise, kidney-specific or not.

Numerous axes and directions are described. Each axis may be transverse,or even perpendicular, with the next so as to establish a Cartesiancoordinate system with an origin point O. One axis may extend along alongitudinal axis of an element. Directions may be indicated by theterms “proximal” and “distal,” and their respective initials “P” and“D,” either of which may be used to describe relative components andfeatures in relation to any axis described herein. Proximal refers to aposition closer to the exterior of the body or a user, whereas distalrefers to a position closer to the interior of the body or further awayfrom the user. Appending the initials “P” or “D” to an element numbersignifies a proximal or distal location, and appending P or D to anarrow in a figure signifies a proximal or distal direction along one ormore axes. Unless claimed, these terms are provided for convenience andnot intended to limit the present disclosure to a particular location,direction, or orientation.

The term “generally” is used to indicate a range of possible values. Forexample, a laser axis L-L is described as being generally transversewith a fiber axis F-F, meaning that axis L-L may be transverse with orperpendicular to axis F-F. The term “generally” also may be synonymouswith other descriptive terms, such as “about,” “substantially,” and/or“approximately,” any of which may indicate a range of possible valuesthat are within +/−5% of a stated value.

As used herein, the terms “comprises,” “comprising,” or like variation,are intended to cover a non-exclusive inclusion, such that a device ormethod that comprises a list of elements does not include only thoseelements, but may include other elements not expressly listed orinherent thereto. Unless stated otherwise, the term “exemplary” is usedin the sense of “example” rather than “ideal.” Conversely, the terms“consists of” and “consisting of” are intended to cover an exclusiveinclusion, such that a device or method that consists of a list ofelements includes only those elements.

One aspect of the present disclosure is depicted in FIG. 1 as a system10. As shown, system 10 may comprise: a fluid cooled optical fiber 12; alaser source 14; a fluid source 16; and a controller 18. Optical fiber12 includes a proximal end 12P coupled with laser source 14 and a fluidsource 16, and a distal end 12D configured to discharge a laser energy 2from laser source 14 and/or a fluid 4 from fluid source 16. Laser source12 and/or fluid source 14 of FIG. 1 may, for example, be configured todischarge laser energy 2 and/or fluid 4 at the same or different timesresponsive to a control signal from controller 18.

An exemplary distal end 12D of optical fiber 12 is depicted in FIGS. 1and 2. As shown, optical fiber 12 may comprise a fiber body 20 includinga distal end 20D; an inner cap 30 surrounding distal end 20D; an outercap 40 surrounding inner cap 30; and a tube 50 extending proximally fromouter cap 40. According to this aspect, tube 50 and outer cap 40 maydefine a proximal or first flow channel 60; outer cap 40 and inner cap30 may define a distal or second flow channel 70; and outer cap 40 maybe configured to place proximal channel 60 in communication with distalchannel 70. Within system 10, fluid 4 (e.g., carbon dioxide or saline)may be circulated through the proximal and distal channels 60 and 70 byfluid source 16.

As shown in FIGS. 1 and 2, fiber body 20 extends along a fiber axis F-Fbetween distal end 20D and a proximal end 20P that is optically coupledto laser source 14. Distal end 20D of FIG. 2 has a side-fireconfiguration including a reflective surface 22 angled to direct laserenergy 2 out of fiber body 20 along a laser axis L-L that is generallytransverse with fiber axis F-F. Distal end 20D may alternatively have anend-fire configuration, wherein surface 22 is either omitted or furthermodified do direct laser energy 2 out distal end 20D so that laser axisL-L is generally parallel with fiber axis F-F. In FIG. 2, a proximalportion of fiber 20 of FIG. 2 includes a cladding 24, whereas a distalportion of fiber 20 does not. Cladding 24 may, for example, have a lowerindex of refraction than fiber body 20, retaining more of laser energy 2in fiber body 20. Proximal end 20P may be optically coupled to lasersource 14 by any conventional means.

In FIG. 2, inner cap 30 surrounds distal end 20D of fiber body 20. Asshown, inner cap 30 may comprise: a proximal end 30P attached to fiberbody 20; a central portion 30C including at least one transmissionportion 32 aligned with the laser axis L-L; a distal end 30D; and aninterior cavity 34 extending between distal end 30D and proximal end30P. Each element of inner cap 30 is now described.

Proximal end 30P of inner cap 30 may be attached to fiber body 20 by afirst epoxy 80. In FIG. 2, first epoxy 80 is configured to fix theposition of inner cap 30 relative to fiber body 20, and/or seal interiorcavity 34. For example, first epoxy 80 may be a first epoxy (e.g., a UVcured epoxy). In FIG. 2, first epoxy 80 covers proximal end 30P of innercap 30 and a distal portion of cladding 24, providing a gradualtransition between cap 30 and body 20. One or more surface features maybe provided on fiber body 20, cladding 24, and/or cap 30 to promoteadhesion with first epoxy 80. For example, the exterior or interiorsurfaces of the proximal end 30P of inner cap 30 may include surfacefeatures configured to promote adhesion with first epoxy 80. Exemplarysurface features may include ridges, indentations, protrusions, threads,or like elements configured to provide an expanded surface areaengageable with epoxy 80. The exterior surface of fiber body 20 may havecomplimentary surface features.

Central portion 30C includes at least one transmission portion 32configured to pass laser energy 2 therethrough. Interior cavity 34 issized to receive fiber body 20 so that laser axis L-L is aligned withtransmission portion 32. For example, as shown in FIG. 2, inner cap 30may be composed entirely of a transmission material (e.g., glass) havinga constant diameter along fiber axis F-F. In this configuration, laseraxis L-L may be aligned with transmission portion 32 in any positionwhere laser energy 2 may be directed through portion 32 from reflectivesurface 22. According to other aspects, inner cap 30 may be composed ofa non-transmission element (e.g., metal) with a variable diameter, andthe at least one transmission portion 32 may include a separatetransmission material attached to cap 30. In this configuration, laseraxis L-L may be aligned with transmission portion 32 in any positionwhere laser energy 2 may be directed through said transmission materialfrom reflective surface 22. However formed, inner cap 30 and at leastone transmission portion 32 may provide a continuous exterior surface ofcap 30, allowing interior cavity 34 to be sealed off from channels 60and 70.

First epoxy 80 may be configured to maintain a separation between theinterior surface of inner cap 30 and the exterior surface of fiber body20. First epoxy 80 may seal interior cavity 34. Once sealed, aninsulative element (e.g., an insulating gas) may be placed inside ofcavity 34. As shown in FIG. 2, for example, an attachment point 36 maybe positioned inside cavity 34 and shaped to surround and/or support atleast a portion of distal end 20D of fiber body 20. The attachment point36 may be formed with a laser energy. For example, inner cap 30 may bemade of a first material, and outer cap 40 may formed of a secondmaterial, such that a portion of caps 30 and 40 may be fused togetherwith the laser energy (e.g., from a CO₂ laser) to define attachmentpoint 36. Laser energy 2 may pass through attachment point 36 or anopening formed therein along laser axis L-L. According to some aspects,attachment point 36 may divide interior cavity 34 into a proximal sealedportion and a distal sealed portion, allowing different insulativeelements to be provided in each sealed portion; or the same element toflow therebetween under direction of heat. Additional attachment points36 may be formed between cap 30 and 40. Similar points 36 may be formedwith first epoxy 80.

In FIG. 2, the interior and exterior surfaces of distal end 30D havesemi-spherical surfaces that are coaxial with fiber axis F-F. Theinterior semi-spherical surface of distal end 30D may include a coatingthat directs laser energy 2 back towards fiber body 20, while theexterior semi-spherical surface of distal end 30D may be configured todirect fluid 4 back into distal cavity 70, as described below.

Outer cap 40 of FIG. 2 surrounds inner cap 30. Cap 40 may comprise: aproximal end 40P attached to inner cap 30; a transfer portion 40Tincluding one or more openings 43; a central portion 40C including anexit port 42 aligned with laser axis L-L; a distal end 40D; and aninterior cavity 44 extending between ends 40D and 40P. The elements ofcap 60 are now described.

Proximal end 40P may be attached inner cap 30 by a second epoxy 82. InFIG. 2, second epoxy 82 is configured to fix the position of outer cap40 relative to inner cap 30, and/or further seal interior cavity 34. Theinterior diameter of proximal end 40P of cap 40 may be sized relative tothe outer diameter of proximal end 30P of cap 30. Second epoxy 82 mayhave at least one property that is the same or different than that offirst epoxy 80. For example, first epoxy 80 may have a thermalresistance and/or elastic modulus greater than that of second epoxy 82.In some aspects, second epoxy 82 may be UV cured epoxy. First and secondepoxies 80 and 82 may be cured by any other means, or be the samematerial.

In FIG. 2, second epoxy 82 covers proximal end 30P of inner cap 30 andthe entirety of first epoxy 80, such that only epoxy 82 is exposed tofluid 4. One or more surface features may be provided on inner cap 30and/or outer cap 40 to promote adhesion with second epoxy 82. Forexample, the interior surfaces of the proximal end 30P of inner cap 30may include surface features (e.g., ridges) configured to promoteadhesion with second epoxy 82. The interior surfaces of outer cap 40and/or the exterior surfaces of first epoxy 80 may include similarsurface features. Much like first epoxy 80, second epoxy 82 may beconfigured to maintain a separation between the interior surface ofouter cap 40 and the exterior surface of inner cap 30. First epoxy 80may be chemically or physically bonded with second epoxy 82 to furthermaintain this separation. For example, first epoxy 80 may be formulatedto meld with second epoxy 82 under application of heat.

Transfer portion 40T includes one or more openings 43 extending throughouter cap 40. The inner and outer diameters of transfer portion 40T aresized to direct fluid 4 into openings 43. Each opening 43 is, forexample, located distal of proximal end 40P of outer cap 40, andproximal of a distal end 50D of tube 50. Openings 43 may be any shape(e.g., circles, ovals, and the like); and size (e.g., the same ordifferent sizes). In FIG. 2, outer cap 40 includes at least two openings43 configured to direct fluid 4 from proximal channel 60 into distalchannel 70. Any number of openings 43 may be provided. These at leasttwo openings 43 may, as in FIG. 2, be arranged oppositely along anopening axis O-O that is transverse or perpendicular with fiber axisF-F.

Central portion 40C includes exit port 42. Interior cavity 44 is sizedto receive inner cap 30 so that both the exit port 42 of outer cap 40and the at least one transmission portion 32 of inner cap 30 are alignedwith laser axis L-L. In FIG. 2, exit port 42 is a through-hole thatextends completely through outer cap 40, and is configured to dischargelaser energy 2 and/or fluid 4 along laser axis L-L. Said through-holemay, for example, be coaxial with laser axis L-L. The diameter ofinterior cavity 44 at central portion 40C is expanded so as to permitattachment with tube 50, and concentrate a greater amount of fluid 4adjacent exit port 42, where a majority of the heat may be generated.Exit port 42 may be configured to focus or dissipate fluid 4.

In FIG. 2, the interior and exterior surfaces of distal end 40D havesemi-spherical surfaces coaxial with fiber axis F-F. Distal end 40D maybe sized relative to distal end 30D of cap 30. For example, in FIG. 2,the interior semi-spherical surface of distal end 40D of outer cap 40may be slightly larger than and spaced apart from the exteriorsemi-spherical of distal end 30D of inner cap 30, defining a returnportion of distal flow channel 70.

As shown in FIG. 2, tube 50 may surround proximal portions of fiber body20, inner cap 30, and/or outer cap 40. Any type of tubing be used. Adistal 50D of tube 50 may be attached to central portion 40C of outercap 40 at a location distal of one or more openings 43 by anyconventional means. As shown in FIG. 1, a proximal end 50P of tube 50may be engageable with fluid source 16 and configured to direct fluid 4through first channel 60. Any type of fluid source may be used.

Proximal and distal flow channels 60 and 70 may be defined by fiber body20, inner cap 30, outer cap 40, and/or tube 50. For example, in FIG. 2,an interior surface of tube 50 is spaced apart from an exterior surfaceof fiber body 20 so that proximal flow channel 60 is defined by tube 50and body 20 as having an annular cross-section about fiber axis F-F. Adistal portion of proximal flow channel 60 is configured to direct fluid4 through transfer portion 40T. The pressure of fluid 4 may be increasedin this configuration. For example, as shown in FIG. 2, the interiordiameter of tube 50 may be constant, while the outer diameter of distalend 40D may be less than the outer diameter of transfer portion 40T,defining a funnel configured to increase the pressure of fluid 4 as itpasses from channel 60 into channel 70.

As noted above, central portion 40C is sized to concentrate a greateramount of fluid 4 adjacent exit port 42. The interior surfaces ofcentral portion 40C may be configured to direct fluid 4 out of exit port42 and/or into the return portion of distal flow channel 70. Forexample, the interior surfaces of transfer portion 40T may includegrooves (or like surface features) configured to direct a first portionof fluid 4 out of exit port 42, and second portion of fluid 4 into saidreturn portion. A first set of grooves may, for example, be spiraledabout the interior of central portion 40C to circulate a portion offluid 4 around port 42, while a second set of grooves may extend alongfiber axis F-F to circulate another portion of fluid 4 through thereturn portion of distal channel 70.

While principles of the present disclosure are described herein withreference to illustrative aspects for particular applications, thedisclosure is not limited thereto. Those having ordinary skill in theart and access to the teachings provided herein will recognizeadditional modifications, applications, aspects, and substitution ofequivalents all fall in the scope of the aspects described herein.Accordingly, the present disclosure is not to be considered as limitedby the foregoing description.

The invention claimed is:
 1. A method of delivering medical treatmentcomprising: inserting a medical device to a treatment area in a patient,wherein the medical device includes an optical fiber with a fiber body,an inner cap surrounding a distal end of the fiber body, an outer capsurrounding the inner cap, and a tube surrounding at least a portion ofthe fiber body and attached to the outer cap; delivering laser energythrough the optical fiber, through a portion of at least the inner cap,and through an opening in the outer cap; and cooling at least a portionof the optical fiber by delivering a fluid through a first flow channelbetween the optical fiber and the tube and through one or more openingsin the outer cap such that the fluid at least partially surrounds adistal portion of the inner cap.
 2. The method of claim 1, wherein thetube is coupled to the outer cap to define the first flow channel, andwherein the inner cap and the outer caps define the second flow channel.3. The method of claim 1, wherein the step of delivering laser energyincludes delivering laser energy via a distal end of the optical fiberthat includes a reflective surface angled to direct laser energy out ofthe medical device along a laser axis.
 4. The method of claim 3, whereinthe inner cap includes a transmission portion aligned with the laseraxis, and wherein the outer cap includes an exit port aligned with thelaser axis.
 5. The method of claim 4, wherein the step of cooling atleast a portion of the optical fiber includes delivering the fluiddistally such that at least a portion of the fluid passes through theexit port in the outer cap.
 6. The method of claim 5, wherein at least aportion of the fluid that passes through the exit port in the outer cappasses through a portion of the second flow channel distally beyond theinner cap.
 7. The method of claim 1, wherein a proximal end of the innercap is attached to the fiber body by a first epoxy.
 8. The method ofclaim 7, wherein the outer cap surrounds a distal end of the inner cap,and wherein a proximal end of the outer cap is attached to the inner capand the fiber body by a second epoxy that includes a thermal resistanceor elastic modulus different from that of the first epoxy.
 9. The methodof claim 1, wherein the fluid passes through the one or more openingsproximal of a distal end of the tube.
 10. The method of claim 1, whereinthe medical device further includes a laser source, a fluid source, anda controller, and wherein the method further includes the controllercontrolling the delivery of the laser energy and the fluid.
 11. A methodof cooling a medical device comprising: coupling a medical device to alaser energy source and to a fluid source, wherein the medical deviceincludes an optical fiber with a fiber body, an inner cap surrounding adistal end of the fiber body, an outer cap surrounding the inner cap,and a tube surrounding at least a portion of the fiber body and attachedto the outer cap; delivering laser energy from the laser energy sourcethrough the optical fiber; and delivering a fluid from the fluid sourcethrough a first flow channel between the optical fiber and the tube,through one or more openings in the outer cap such that the fluid flowsthrough a second flow channel between the outer cap and the inner cap.12. The method of claim 11, wherein the delivered fluid at leastpartially surrounds a distal portion of the inner cap.
 13. The method ofclaim 11, wherein the fluid passes through the one or more openingsproximal of a distal end of the tube.
 14. The method of claim 11,wherein at least a portion of the fluid passes through an exit port inthe outer cap, and wherein at least a portion of the fluid that passesthrough the exit port in the outer cap passes through a portion of thesecond flow channel distally beyond the inner cap.
 15. The method ofclaim 11, wherein the laser energy is delivered through the opticalfiber at the same time as the fluid is delivered through the first andsecond flow channels.
 16. A method of delivering medical treatmentcomprising: inserting a medical device to a treatment area in a patient,wherein the medical device includes an optical fiber with a fiber body,an inner cap surrounding a distal end of the fiber body, an outer capsurrounding the inner cap, and a tube surrounding at least a portion ofthe fiber body and attached to the outer cap; delivering laser energythrough the optical fiber and through portions of at least the inner capand the outer cap such that the laser energy is delivered through anexit port in the outer cap; and delivering a fluid through a first flowchannel between the optical fiber and the tube and through one or moreopenings in the outer cap such that the fluid at least partiallysurrounds a distal portion of the inner cap, wherein the one or moreopenings are positioned proximal to the distal end of the tube.
 17. Themethod of claim 16, wherein the laser energy and the fluid are deliveredat the same time.
 18. The method of claim 16, wherein the laser energyand the fluid are delivered at different times.
 19. The method of claim16, wherein the inner cap includes at least a portion formed of atransmission material.
 20. The method of claim 19, wherein the inner capis formed entirely of glass, and wherein the outer cap is formed of ametal.